There are known cleaning sheets that are used by being attached to a head of a cleaning tool which further includes a handle connected to the head. Some types of these cleaning sheets are known to have a multitude of long fibers.
For example, Patent Literature 1 discloses a cleaning sheet having a heat-fusible sheet and a multitude of heat-fusible long fibers extending in one direction and joined to the heat-fusible sheet by a plurality of melt-bonding sections that extend continuously in a direction intersecting the long fibers and that are disposed intermittently in the direction in which the heat-fusible long fibers extend.
In the cleaning sheet of Patent Literature 1, however, the heat-fusible long fibers are joined to the heat-fusible sheet by the continuously-extending melt-bonding sections. Such a structure limits the degree of freedom of the heat-fusible long fibers between adjacent melt-bonding sections, whereby it is difficult to improve the dirt trapping capabilities. Further, the heat-fusible long fibers may get caught in objects-being-cleaned.
In order to increase the degree of freedom of heat-fusible long fibers, Patent Literature 2 discloses a method for making a cleaning sheet including a step of cutting the multitude of heat-fusible long fibers between adjacent melt-bonding sections to divide the length of the heat-fusible long fiber into two halves.
However, in the cleaning sheet made by the method disclosed in Patent Literature 2, the heat-fusible long fibers are joined to the heat-fusible sheet only by the continuously-extending melt-bonding sections and are thus integrated with the sheet. Therefore, the heat-fusible long fibers cannot move freely in the form of an aggregated bundle of long fibers, whereby it is difficult to improve the dirt trapping capabilities.
Meanwhile, Patent Literature 3 also discloses a cleaning sheet including a multitude of heat-fusible long fibers having different lengths by cutting the heat-fusible long fibers between adjacent continuously-extending melt-bonding sections, in order to increase the degree of freedom of heat-fusible long fibers.
In the cleaning sheet of Patent Literature 3, however, the heat-fusible long fibers are cut by an intermittent cutting line arranged between adjacent continuously-extending melt-bonding sections in the same direction as the continuously-extending melt-bonding sections, and therefore, not all of the heat-fusible long fibers between the adjacent melt-bonding sections are completely cut apart. Such a structure limits the degree of freedom of the heat-fusible long fibers between the adjacent continuously-extending melt-bonding sections. Further, in this Patent Literature, the length of the thus-cut heat-fusible long fibers possessed by one of the adjacent continuously-extending melt-bonding sections differs from the length of the long fibers possessed by the other melt-bonding section. However, the length of all the heat-fusible long fibers possessed by either the one or the other melt-bonding section is uniform. Thus there is no randomness in the lengths of the heat-fusible long fibers, whereby it is difficult to improve the dirt trapping capabilities.
Patent Literature 1: U.S. Pat. No. 6,329,308 B1
Patent Literature 2: EP 0777997 A2
Patent Literature 3: JP-A-2000-245670